duffy_paul (pau–(at)–verest.tandem.com) wrote:
: Anyone know the output impedances of various power tubes, especially
: the EL34 and 6L6 and 6V6? I was looking through the Pittman book
: and could find suggested load resistance and plate to plate resistance
: but no output impedance.

Those are the figures of merit. You won’t find “output impedance” listed
in a tube manual. The recommended plate-to-plate load impedance is the
figure to look for.

: I have a Soldano SLO-100 which I would like to run EL34’s in, but
: Soldano says it won’t work because the output impedance of EL34’s
: is so different from that of 6L6’s.

He’s full of it. Both types will work well into the same plate-to-plate
load (typically 4K-5K for most amps). Most likely, his power transformer
can’t handle the extra heater current demands of the EL34, but he doesn’t
want to admit it. It’s funny, but I usually convert the other way
around; namely, setting up EL34 amps for 6L6GCs. I guess it’s all a
matter of taste. The 6L6s are certainly more rugged.